‘Daydream’ switch stays on in ADHD

U. NOTTINGHAM (UK) — New evidence suggests children with ADHD have trouble switching off the “daydreaming” regions in the brain that often interfere with concentration, particularly on tedious tasks.

Using a “Whac-a-Mole” style game, researchers found evidence from brain scans that children with ADHD require either much greater incentives—or their usual stimulant medication—to switch off those regions and focus on a task. The findings are published in the Journal of Child Psychology and Psychiatry.

“The results are exciting because for the first time we are beginning to understand how in children with ADHD incentives and stimulant medication work in a similar way to alter patterns of brain activity and enable them to concentrate and focus better,” says Chris Hollis, a professor of health sciences at the University of Nottingham. “It also explains why in children with ADHD their performance is often so variable and inconsistent, depending as it does on their interest in a particular task.”

Children with ADHD are excessively restless, impulsive, and distractible, often leading to difficulties at home and school. Previous studies have shown that these children have difficulty in switching off the default mode network (DMN) in their brains.

This network is usually active when we are doing nothing, giving rise to spontaneous thoughts or “daydreams”, but is suppressed when we are focused on the task before us. In children with ADHD, however, it is thought that the DMN may be insufficiently suppressed on “boring” tasks that require focused attention.

The active regions in this MRI scan pinpoint brain areas that the children with ADHD failed to deactivate during low-incentive tests, as compared with the control children, whose brain scans showed no difference between low- or high-incentive conditions. (Credit: University of Nottingham)

Researchers compared brain scans of 18 children with ADHD, between the ages of nine and 15 years old, against scans of a similar group of children without the condition as both groups took part in a task designed to test how well they were able to control their behavior.

Using MRI scans, they measured brain activity while the children played a computer game in which green aliens were randomly interspersed with less frequent black aliens, each appearing for a short interval. Their task was to “catch” as many green aliens as possible, while avoiding catching black aliens. For each slow or missed response, they would lose one point; they would gain one point for each timely response.

To study the effect of incentives, the reward for avoiding catching the black alien was then increased to five points, with a five-point penalty incurred for catching the wrong alien.

Brain scans showed that typically developing children switched off their DMN network whenever they saw an item requiring their attention. However, unless the incentive was high, or they had taken their medication, the children with ADHD would fail to switch off the DMN and would perform poorly.

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This effect of incentives was not seen in children without ADHD—activity in their DMN was switched off by items requiring their attention regardless of the incentive on offer.

“Using brain imaging we have been able to see inside the children’s heads and observe what it is about ADHD that is stopping them concentrating. Most people are able to control their ‘daydreaming’ state and focus on the task at hand. This is not the case with children with ADHD,” says research collaborator Martin Batty.

“If a task is not sufficiently interesting, they cannot switch off their background brain activity and they are easily distracted. Making a task more interesting—or providing methylphenidate (known by the brand name Ritalin)—turns down the volume and allows them to concentrate,” adds Batty.

“These findings help explain one of the interesting characteristics of ADHD—that children with the condition appear able to control themselves much better when motivated to do so,” says researcher Elizabeth Liddle.

“The common complaint about children with ADHD is that ‘he can concentrate and control himself fine when he wants to’, so some people just think the child is being naughty when he misbehaves. We have shown that this may be a very real difficulty for them. The off-switch for their ‘internal world’ seems to need a greater incentive to function properly and allow them to attend to their task.”

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6 Comments

Stimulant medication doesn’t just “take away” ADHD either. Counseling helps but the child has to learn to cope with the extra challenges they face. Also ADHD, doesn’t disappear in adulthood, most adults continue to need medication and or need to have developed coping strategies. Although the hyperactivity usually doesn’t persist into adulthood, the distractabilty usually does. ADHD though often gives people uniquely creative ways of looking at the world so it is not without its gifts.

Michelle F January 12, 2011

My husband and my son both have ADHD. This article doesn’t mention that people with ADHD are frequently very smart and learn very quickly. I agree with Jana, especially her last sentence. As Adrian Monk would say, “It’s a blessing and a curse.”

Manon January 12, 2011

I agree with Jana and Michelle, that they are very special and unique people. That said, as parent, we need to know what to say and do in order to help them develop strategies. Any suggestions? Does listening to music while doing a task for example helps them focus better?? We cannot constantly provide incentives, they have to learn to get it from within…

Chan February 11, 2014

Great study

http://www.ask.com September 22, 2014

Your style is really unique compared to other folks I have read stuff from.

Many thanks for posting when you have the opportunity, Guess I will just book mark this site.

garygech December 18, 2014

ADHD is not one disorder, but a family of disorders, likely related to a membrane transport protein that controls a membrane channel like cystic fibrosis. Unlike cystic fibrosis, which is pulmonary, ADHD affects the brain, thus the affects appear to be psychiatric.

ADHD appears to respect a 300-500 millisecond circuit, just watch a child with ADHD. The major variants appear to be ADHD-Inattentive, a very challenging substitute often related to intrauterine drug use exposure, an addicted mother, ADHD-Mixed, another family of disorders, and ADHD-Hyperactive, a very specific challenge, because these children are highly intelligent and actually do think different. Such short tempered ADHD-H children can learn anger management strategies, and seem to respond to “tough love”. The transference of emotional language structures can be developed. ADHD-Inattentive is very challenging, because these students become disengaged. ADHD-Mixed, a variety of challenges we do not understand, seems to respond in the short term to certain stimulants, but in the long term, outcomes relate to family structure and not psychology or medication. There is no evidence based data that the disorder is psychiatric or psychologic, but all evidence, like dementia, points to a neurological cause. The difference with ADHD is children grow up, and their abilities can be guided through cultural adaption.